<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        a:link {color: red}		/* 未访问的链接 */
        a:visited {color: green}	/* 已访问的链接 */
        a:hover {color: blue}	/* 鼠标移动到链接上 */
        a:active {color: yellow}	/* 选定的链接 */
    </style>
</head>
<body>
<a href="http://www.baidu.com">百度</a>
</body>
</html>